Fix TiddlySaver 1

This allows TW Classic to load/save with TiddlySaver by changing the 'restrictToSameDirectory' flag. I removed all the javadoc updates from my last attempt (now deleted) to make the changes more obvious. Will update javadoc when/if I rewrite the restriction code; not sure it's needed as a good policy file ensures this, but will revisit later.

Tested with TW Classic (a 2.7.0 prerelease I had around) with the following policy file (assuming Windows location `C:\TW`:
```
grant codeBase "file:C:/TW/TiddlySaver.jar" {
	permission java.io.FilePermission "<<ALL FILES>>", "read";
	permission java.io.FilePermission "C:${/}TW${/}*", "write";
};
```